1. Field of the Invention
The present invention relates generally to prosthetic joints and pertains, more specifically, to an improvement in a prosthetic joint wherein component parts of the prosthetic joint are provided with structural features for deflecting surrounding soft tissue away from sharp edges which may be present at an implant site, during articulation of the prosthetic joint.
2. Description of the Related Prior Art
Prosthetic joints include component parts which are affixed to the natural bone at an implant site and which are held together by surrounding soft tissue for articulation of the component parts relative to one another. In a knee prosthesis, for example, a femoral component and a tibial component are held by collateral ligaments and by cruciate ligaments in an articulation relationship for appropriate flexion and extension of the knee prosthesis. Each component of the knee prosthesis is seated upon natural bone at the implant site, along a prepared area of a corresponding bone, the implant component being provided with a seating area for engaging the corresponding bone along the prepared area. The seating area is defined precisely by a relatively sharp peripheral edge so as to attain a desired well-seated engagement between the implant component and the prepared bone at the implant site. However, because of variations among recipients in the configuration of the natural bone at an implant site, a seated prosthetic implant component may extend beyond at least a portion of the peripheral boundary of the prepared area of the bone at the implant site, with the result that at least a portion of the sharp peripheral edge along the periphery of the seating surface will become exposed. These exposed sharp edges, if allowed to come into contact with soft tissue at the implant site, and especially a cruciate ligament during articulation of the prosthetic knee, can cause irritation of the ligament and eventual serious injury.